- Pertussis occurs most commonly in infants younger than 6 months but can occur in any age group.
- The initial or catarrhal stage is characterized by upper respiratory tract symptoms and lasts 7 to 10 days. This is followed by a paroxysmal phase characterized by episodic bouts of staccato cough lasting 2 to 4 weeks.
- Diagnosis is usually based on history and physical examination. Fluorescent antibody testing is currently the most utilized confirmatory test, but it has a low sensitivity and poor predictive value. The polymerase chain reaction test has a much higher sensitivity.
- The mainstay of treatment is supportive therapy including oxygen for hypoxia and intravenous fluids for dehydration. Erythromycin is an effective therapy only if given prior to the paroxysmal stage.
- Prophylactic therapy should be given to close contacts.
- Indications for hospital admission include young age (younger than 1 year), hypoxia, and dehydration.
Pertussis is an acute, bacterial, highly contagious, respiratory infection with a significant associated morbidity and mortality, especially in infants. In spite of widespread vaccination, the incidence of pertussis has been increasing, especially in adolescents and young adults.1–3 Pertussis or “whooping cough” is characterized by severe episodes of coughing followed by a forceful inspiration against a partially closed glottis, which causes the “classic whooping sound.”
In the prevaccine era, pertussis was the number one cause of death in children (age ≤ 13 years old) from a communicable disease in the United States. Pertussis accounted for more infant deaths than diphtheria, poliomyelitis, measles, and scarlet fever combined.4 Worldwide, on an annual basis, there are 60 million cases of pertussis with more than half a million deaths. In developing countries and in countries where vaccination rates are low, a high incidence of pertussis continues.4
After the introduction of a vaccine in the United States in 1940s, the incidence of pertussis declined precipitously, from approximately 250 000 cases yearly in the 1930s to just more than 1000 cases in 1976.5,6 Since then, the incidence has been rising worldwide, including in the United States with 25 827 cases in 2004.6 The actual incidence of pertussis is much greater since pertussis is significantly underreported.7 The rates of reported pertussis are estimated to be 40- to 160-fold less than actual rates, with asymptomatic infections 4 to 22 times more common than symptomatic infection.8 The rising incidence is due to multiple factors: waning immunity after childhood immunization, better diagnostic tests, greater health care provider awareness, improved reporting techniques, and decreased pertussis immunization in certain patient populations such as immigrants and those unimmunized for religious or other reasons.9
Pertussis is caused by Bordetella pertussis. B. pertussis belongs to the Bordetella genus of bacteria, which are small gram-negative fastidious pleomorphic coccobacilli that are very difficult to grow. They require special media for culture, which makes a definitive diagnosis by culture challenging. Other Bordetella species can also cause disease. B. parapertussis...